Weird partial (possibly kernel) hang of ubuntu guest under opencore host

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I have a Mac 15,1 (late 2014 5k imac) running Sonoma via OpenCore.

Linux athanhome 6.5.0-28-generic #29-Ubuntu SMP PREEMPT_DYNAMIC Thu Mar 28 23:46:48 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

OS X 14.4.1 (23E224)

VirtualBox Version 7.0.14 r161095 (Qt5.15.2)

After upgrading to Sonoma/OpenCore from Ventura/OpenCore, and upgrading to some version of VB prior to 7.0.14, I started experiencing occasional full system hangs (including host os). Then, after upgrading to 7.0.14 a while back (fyi, currently, check for update does not show 7.0.18, but I will seek it out and try it), the host hangs went away but the guest (Ubuntu Linux) occasionally appears to lock up, but not completely. See list below.

I note that certain operations are hanging but not all. E.g. DNS fails (ping to hostname had to be keyboard interrupted, but ping to IP works). systemctl's to status or restart resolved had to be keyboard interrupted. console was not echoing keystrokes.

I have not yet found a way to unstick whatever is stuck. I could use some suggestions in order to more precisely locate what component of the guest is stuck. It's not the network, since ssh does eventually get in. But the console is hung.

I have been using "reset" of the guest hardware from the VBox menu to restore the system to fully operational status. This happens intermittently several times a week and may be related to the host going into sleep, because I most frequently notice the problem when returning to the system after extended AFK.

(1) The console window does not seem to accept input -- login: prompt does not echo any keypresses there

(2) left this running for days in an ssh session, and it was still running ok:

while true;do sleep 30;date;done
#... removed
Tue May  7 07:23:56 PDT 2024
Tue May  7 07:24:26 PDT 2024
Tue May  7 07:24:56 PDT 2024
Tue May  7 07:25:26 PDT 2024
Tue May  7 07:25:56 PDT 2024
Tue May  7 07:26:26 PDT 2024
Tue May  7 07:26:56 PDT 2024

(3) but new ssh sessions to the machine take a very long time, which in the past I know can happen due to failed dns

(4) once logged in, ^{C indicates interrupt after the command hangs:}

# ping www.yahoo.com
^C
root@xx:/home/yy# netstat -rn
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
0.0.0.0         xx.xx.xx.1    0.0.0.0         UG        0 0          0 enp0s3
xx.xx.xx.0    0.0.0.0         255.255.255.0   U         0 0          0 enp0s3
root@xx:/home/yy# ping xx.xx.xx.1
PING xx.xx.xx.1 (xx.xx.xx.1) 56(84) bytes of data.
64 bytes from xx.xx.xx.1: icmp_seq=1 ttl=64 time=4.84 ms
64 bytes from xx.xx.xx.1: icmp_seq=2 ttl=64 time=1.90 ms
^C
--- xx.xx.xx.1 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 1.903/3.370/4.838/1.467 ms
root@xx:/home/yy# systemctl status systemd-resolved
^C
root@xx:/home/yy# systemctl restart systemd-resolved
^C
root@xx:/home/yy# top
top - 07:40:09 up 7 days, 15:47,  6 users,  load average: 11.33, 11.08, 10.86
Tasks: 4096 total,   1 running, 171 sleeping,   0 stopped, 3924 zombie
%Cpu(s):  0.3 us,  1.0 sy,  0.0 ni, 98.7 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
MiB Mem :   1958.7 total,    288.9 free,    545.2 used,   1308.0 buff/cache
MiB Swap:   1048.0 total,    996.6 free,     51.4 used.   1413.4 avail Mem

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
 145637 root      20   0   16164  11136   3840 R   2.6   0.6   0:00.40 top
     33 root      20   0       0      0      0 S   0.3   0.0   1:42.23 kcompactd0
    649 courier   20   0    6204   3328   3200 S   0.3   0.2   0:15.24 couriertcpd
      1 root      20   0  170300   8780   5708 D   0.0   0.4   0:24.25 systemd
      2 root      20   0       0      0      0 S   0.0   0.0   0:00.12 kthreadd
      3 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 rcu_gp
      4 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 rcu_par_gp
      5 root       0 -20       0      0      0 I   0.0   0.0   0:00.00 slub_flushwq